Add method to get of currencies list (#182)

lib/RetailCrm/Methods/V5/References.php

@@ -284,4 +284,22 @@ trait References
             ['unit' => json_encode($unit)]
         );
     }
+
+    /**
+     * Get a list of currencies
+     *
+     * @throws \InvalidArgumentException
+     * @throws \RetailCrm\Exception\CurlException
+     * @throws \RetailCrm\Exception\InvalidJsonException
+     *
+     * @return \RetailCrm\Response\ApiResponse
+     */
+    public function currenciesList()
+    {
+        /* @noinspection PhpUndefinedMethodInspection */
+        return $this->client->makeRequest(
+            '/reference/currencies',
+            "GET"
+        );
+    }
 }

tests/RetailCrm/Tests/Methods/Version5/ApiClientReferenceTest.php

@@ -184,7 +184,8 @@ class ApiClientReferenceTest extends TestCase
             ['stores'],
             ['couriers'],
             ['costs'],
-            ['units']
+            ['units'],
+            ['currencies'],
         ];
     }